Most of my
students through the years have come to jazz by way of rock guitar (as
I did in the late 60s/early 70s). They almost always know one or two pentatonic
scale "box patterns"; most of them are more comfortable with minor pentatonic
scales. Understandably, they feel trapped by these "boxes" and want to
give them up!

However,
there's a lot of untapped mileage in those boxes. Examples 1 and 2 show
two minor pentatonic scales in a very familiar fingerboard area for most
of us. Let's briefly examine the tones contained in the patterns, then
see how they could be used to build lines on a typical Dm7 - G7 turnaround
(ii-V7 in the key of C):

Example
1 is an A minor pentatonic scale. The five tones in this scale are
A, C, D, E and G. Most of us ran into this one when we were getting our
rock improvising chops together, and we immediately think something like
"Blues licks in A" or "REO Speedwagon". (Yes, I'm dating myself here!)

It just so
happens that the tones A, C, D, E and G apply to chords other than A minor.
For example, let's consider D minor: A is the 5th of D minor, C is the
7th, D is the root, E is the 9th and G is the 11th. So this "A minor pentatonic
scale" could be used over a D minor chord, or a D minor 7th, or a D minor
9th, or a D minor 11th. It doesn't contain all the notes in a D minor
chord (F, the 3rd of D minor, is absent). Still, it will sound fine against
a Dm chord; the 9th and 11th are extensions of the basic chord.

Example
2 is the same pattern raised by a half-step to produce a Bb minor
pentatonic scale. The tones are Bb, Db, Eb, F and Ab. This scale sounds
good on Bb minor chords, of course. Another interesting use of this scale
would be on an altered G dominant seventh chord; the five tones could
be the #9th (A#, spelled as Bb), b5th (Db), #5th (D#, spelled as Eb),
7th (F) and b9th (Ab) of a G7 chord. In other words, this scale has all
the possible alterations you could play on a G7!

Let's recap:
I'm using an A minor pentatonic scale on a D minor chord (the scale root
is a 5th up from the chord's root) and a Bb minor pentatonic scale on
a G7 altered chord (the scale root is a minor 3rd up from the chord's
root). Also important to remember is that the two scales are just a half-step
apart.

Play
example 3

Play
example 4

Examples
3 and 4 are a couple of different lines I made up using these two
scales on a Dm7 - G7 - Cmaj7 chord progression. Although they use scales
you might previously have regarded as rock guitar fodder, they don't sound
like rock and roll at all. A couple of observations:

1. Notice
my avoidance of the all-too-common "straight up and down the scale" approach;
we've all heard that much too often! The lines use wide intervals at times
and change direction to try to create some melodic interest.

2. The roots
of the chords are not very prominently featured in the lines. That's not
to say you should never use the root in your lines; I personally try not
to overemphasize the root because it's the most obvious note in the chord.
I think common jazz practice (at least, in the last 40 years or so) bears
me out pretty well.

3. The lines
basically have an eighth-note pulse like a lot of bop lines, but I tried
to slip in the occasional rest, tie or longer note to let the lines 'breathe'
a little. Think about people you know who seem to talk constantly. No
matter how well-intentioned they are, they usually tend to get on your
nerves, don't they? Good conversation has pauses and internal rhythms;
it gives the listener a chance to 'catch up' once in a while. It also
can give a listener the pleasure of anticipating what's coming next. I
think improvising should be like that too. (I need to pause periodically
when I'm playing so I can guess what's coming next!)

There are
many more uses for pentatonic scales; we've just scratched the surface
here. To hear masters of the pentatonic scale in action, check out recordings
by Woody Shaw, McCoy Tyner, Bob Berg and John Scofield, to name a quick
few. To read more about pentatonic usage, try The Advancing Guitarist
by Mick Goodrick or The Jazz Theory Book by Mark Levine. Both of these
books have excellent sections on the pentatonic scale. (Goodrick's book
does a great job discussing different possible fingerings for pentatonic
scales and why you might use them.)

Have fun
trying these ideas! I hope they will serve as springboards for your imagination
and will spark ideas of your own.